Pulling device



March 21, 1967 J. c. REIB PULLING DEVICE 2 Sheets-Sheet 1 Original FiledDec.

' "*INVENTOR.

JOHN c. REIB ATTORNEY 21, 1967 J. c. RElB 3,310,210

PULLING DEVICE Griginal Filed Dec. 5, 1963 2 Sheets-Sheet 2 INVENTOR.JOHN C. RE I B BY gwbw ATTORNEY United States Patent 3,310,210 PULLINGDEVICE John C. Reib, R0. Box 738, Franklin, Pa. 16323 Continuation ofabandoned application Ser. No. 327,605, Dec. 3, 1963. This applicationMar. 7, 1966, Ser. No.

6 Claims. (Cl. 226-1) This application is a continuation of Ser. No.327,605, filed Dec. 3, 1963 and now abandoned.

This invention relates to a pulling device and more particularly to apuller designed for pulling newly formed plastic pipe from an extrusiondevice through a vacuum sizer.

Pipe pullers of various designs are well known in the art ofmanufacturing plastic pipe and have proven satisfactory under someconditions. Such devices of the prior art have suffered mainly from thedisadvantages of not being readily or rapidly adjustable to accommodatevariations in the size of the pipe, especially those variationsassociated with the start-up of the pipe forming process. At start-upthe first portion of pipe'being formed is likely to be a small diameter,more or less solid, rope of plastic material extending from theextrusion device through the vacuum sizer dies into the pullerapparatus. Such material is usable only as a means for applying tensionat a controlled rate to the tubing later emitted by the extrusion deviceand having the desirable size applied by the vacuum sizer to formusuable pipe. A typical situation would find a rope of plastic materialof a diameter of approximately one-half inch constituting the primarymaterial being fed into the puller apparatus to begin the formation of apipe of perhaps four inches in diameter. Under such conditions it willbe seen that resilience and adjustability are prime requisites of thegripping surfaces in the puller apparatus.

Another set of circumstances in which rapid adjustability is necessaryoccurs when certain conditions associated with the extrusion devicecause the formation of a slug or blob of plastic material as part of therope of plastic material between the forming die of the extrusion deviceand the pulling apparatus and having a diameter much greater than thatof the rope of plastic material. With devices of the prior art such aslug usually stopped the pulling action and gave rise to the necessityfor restarting the whole process. The present device is designed toaccommodate such slugs or blobs without interrupting the pulling action.All of the above described accommodations to the variations in sizebetween rope and pipe or between rope and slug of material areaccomplished without change in the pulling speed and without substantialchange in gripping force exerted upon the material being pulled.

A further disadvantage of prior devices, overcome by the apparatus ofthe present invention, is flattening of the pipe when, due to variationsin extrusion conditions, the wall of the pipe becomes thinner thannormal. The present device applies gripping force of substantiallyuniform pressure over an area of the pipe much greater than thatutilized by prior machines of equivalent size and thus less tendency toflatten the pipe when thin walled pipe is being produced.

The apparatus of the present invention comprises a pair of automotivetype wheels provided with the usual pneumatic tires and journaled onparallel axles with the tread surfaces of the tires in contact with eachother. Butyl rubber tires such as commonly used on aircraft have beenfound most satisfactory because of greater softness and flexibility. Thetwo wheels are synchnonously driven in counter-rotation so that a pieceof pipe or other elongated object placed in contact with the treads onone side 3,310,210 Patented Mar. 21, 1967 of the machine will be drawnthrough between the treads of the tires in a smooth continuous motion.The axis of one of the wheels is fixed while the other wheel, usuallythe upper one, is journaled on an axle transversely movable withrelation to the axis of the lower wheel and controlled in such motion bya fluid operate-d extensible cylinder under either automatic or manualcontrol to regulate the distance between the tread surfaces and tocontrol the pressure applied by the tread surfaces to any object passingbetween them.

These and other advantages of the present invention will become morereadily apparent on further consideration of the following descriptionand drawings in which:

FIG. 1 is a side elevational view partly in section of a pullingapparatus constructed according to the principles of this invention; and

FIG. 2 is a front elevational view partly in section of the device shownin FIGURE 1.

In FIGURE 1 there is shown a pulling apparatus constructed according tothe principles of this invention and comprising a generally rectangularframe structure 6 having a base portion 8 supported by a plurality ofadjustable legs 10 on a generally horizontal floor surface 12 so thatadjustment of height to maintain a constant centerline for differentpipe diameters and leveling of the frame structure 6 can be accomplishedby the adjusting of the legs 10. Extending upwardly from the baseportion 8 and rigidly secured thereto is a pair of generally parallelspaced substantially rectangular side plates 14 and 16 being left andright side plates respectively, as viewed in FIGURE 2. A flat generallyrectangular top plate 18 is rigidly secured at the top edges of the sideplates 14 and 16 to which the top plate 18 is joined by suitable cornerbracing to form the rigid frame structure 6. The base portion 8 isprovided with a plurality of casters or wheels 20 to support theapparatus when the legs 10 are retracted and provide for mobility of theapparatus when it becomes necessary to move the apparatus from one placeto another. An elongated horizontal shaft or lower axle 22 spacedupwardly from the base portion 8 and parallel thereto is suitablyjournaled and rotatably supported by hearing members mounted on ahorizontal lower frame 28 rigidly secured to and supported by the sideplates 14- and 16. The lower axle 22 extends transversely across theframe structure 6 from a point inwardly adjacent the righthand sideplate 16 through the lefthand side plate 14 and far enough therebeyondto provide for mounting of an automotive type wheel 24 upon a hub disc25 rigidly secured to the lefthand end of the lower axle 22 anddrivingly rotatable therewith. An automotive pneumatic tire 26 ismounted on the wheel 24 in the usual manner and inflated to a pressuredetermined by the desired amount of wrap around and gripping force,normally only a few pounds per square inch.

The tires are desirably inflated to only a few pounds per square inchand as a consequence readily conform to the shape of the pipe to such adegree that on pipe of 4%; inch diameter each tire can contact an areameasuring approximately 3 inches (circumferentially) by 12 to 14 inches(axially) for a total contact area of more than square inches for bothtires. Such a contact area could be achived by prior devices only bylengthening the machine to five feet or more as compared with a lengthof approximately 30 inches for the apparatus of the present invention.The amount of contact area is readily controlled by adjusting the tirepressure relative to the pres- An upper axle 30 similar to axle 22,parallel thereto and upwardly spaced therefrom, is similarly providedwith a hub disc 25, a wheel 24 and a tire 26. The upper axle 30 isjournaled in the same manner as lower axle 22 excepting only that thebearing elements rotatably supporting the upper axle 30 are suitablymounted upon an upper frame 32 slidably mounted on a plurality ofelongated, vertical guide elements 34 extending from the lower frame 28to the top plate 18 and rigidly secured thereto. The frame 32 isvertically adjustable and controlled in such adjustment by an elongatedfluid actuated extensible cylinder 36 having a base portion supported bythe lower frame 28 and extensible rod and rigidly connected to the underside of the upper frame 32 so that suitable activation of the cylinder36 can raise the upper axle 30 to any desired height while activation ofthe cylinder 36 in the opposite direction can lower the upper tire 26into contact with the lower tire 26 and apply any desired amount ofdownward force thereto. Suitable fluid conducting connections 38 and 39connect the base end and the rod end respectively of the cylinder 36 toa remote valve means, not shown, of a type well known in the art forselectively pressurizing either the rod end or the base end of thecylinder 36 to accomplish upward and downward adjustment of the upperaxle 30. The connections 38 and 39 communicate with a manually operatedreversing valve 42 of a type well known in the art whereby thecommunication of the connections 38 and 39 with the remote valve can bereversed by actuation of the reversing valve 4-2 so that the pressurenominally applied to the rod end connection 39 can be instantaneouslytransferred to pressurize the base end connection 38. The manual controlof the reversing valve 42 is connected by suitable levers and linkage toan elongated shaft 44 extending transversely of the frame structure 6from the righthand side plate 16 through the lefthand side plate 14 andout beyond the lower tire 26 where it terminates in a ball endedupwardly extending handle member 46 which extends upwardly near theplane of contact of the upper tire and lower tire 26 and is so locatedforwardly of the contacting portions of these tires as a control handleor a safety device which is activated by pressure of a workmans arm, forexample, traveling toward the contact area which causes the shaft 44 torotate in a counterclockwise direction as seen in FIGURE 1. Suchrotation of the shaft 44 activates reversing valve 42 transferringpressure from the rod end connection 39 to the base end connection 38and results in lifting of the upper tire 26 out of contact with thelower tire 26 so that no injury to the workman results.

A suitable motor 56 is mounted on the base portion 8 and is drivinglyconnected either directly or by sprocket and chain (not shown) to avariable speed reducing gear unit 52 having a vertically upwardlyextending output shaft 54 coupled to an elongated vertically extendingdrive shaft 56 the top end of which is suitably rotatably journaled atthe under side of the top plate 18 for rotation about a vertical axis ina well known manner. An angle drive lower gear box 58 mounted on thelower axle 22 drivingly connects the drive shaft 56 with the lower axle22 to provide variable speed rotation thereto. The drive shaft 56extends upwardly through the upper frame 32 and is slidably drivinglyengaged in an angle drive gear box 60 mounted on the upper axle 30 todrivingly connect the drive shaft 56 and the upper axle 36 for poweredvariable speed rotation of the axle 30. It is of course necessary thatan elongated keyway such as that shown at 62 on the upper part of thedrive shaft 56 or a plurality of elongated splines be provided so thatthe angle drive gearbox 60 can be elevated and lowered without losingtis driving connection to the drive shaft 56.

A manually operated control handle 68 is shown mounted on the gear unit52 to provide selective speed control for the tires 26 since speedcontrol is vital in many pulling operations. Such control can be of theremote type and mounted at any convenient position.

The device of this invention is usable for the application of continuoustension to various elongated objects of different or varying crosssection including rectangular and triangular shapes, but operation ofthis device will be described in relation to the production of plasticpipe to avoid cumbersome circurnlocutions.

In operation the device of this invention is placed adjacent a means forforming a plastic object such as a vacuum sizer as described in mycopending application Serial No. 306,554, filed September 4, 1963, andis spaced rom and aligned with such source by proper activation of theadjustable legs 10 and a spacing element (not shown) to prevent thesource from moving toward the pulling apparatus as a result of thetension applied to the plastic pipe. A piece of plastic pipe 64 is shownengaged between the upper and lower tires 26 and may for an example havea diameter of approximately four inches. A portion of the newly formedplastic object is manually inserted between the tires 26. At thebeginning the plastic o'bpect may be a more or less solid rope ofperhaps one inch in diameter which must be grasped by the tires so thattension is applied thereto. Rotation of the tires in the indicateddirection clockwise for the upper tire and counterclockwise for thelower tire (as viewed in FIG. 1) is accomplished by energizing the motor50 from suitable electric controls (not shown) so that operation of themotor 50 acting through the gearbox 52 causes rotation of the driveshaft 56 and the axles 22 and 30 in the proper direction to give poweredrotation to the tires 26. Such rotation of the tires 26 applies tensionto the pipe 64; causing it to move from right to left as viewed inFIGURE 1. Pressurizing the rod end of the cylinder 36 through the rodend connection 39 applies a downward force to the upper tire 26 which inturn applies frictional force to the pipe 64 proportional to the amountof pressure admitted to the rod end of the cylinder 36 and is entirelycontrollable in amount by a control valve of a type well known in theart.

It is to be appreciated that whenever desirable, as at the beginning ofthe operation, the base end of the cylinder 36 can be pressurized toraise he upper tire 26 out of contact with the lower tire 26 to allowthe plastic object to 'be placed in position resting on the lower tire26 after which pressurization of the rod end of the cylinder 36 throughthe rod end connection 39 lowers the upper tire 26 into the positionshown in the figures.

The motion of a plastic object such as pipe 64 from right to left innormal operation is a relatively slow movements so that if desirable aworkman can grasp the pipe 64 for instance with a pair of calipers orother tool for measuring the diameter and due to the slowness of themotion might allow the tool or his hands to be drawn into the area ofcontact between the two tires. Because of this possibility, the handlemember 46 is, if desired, positioned forwardly of the contact area ofthe two tires so that it will be activated as hereinbefore described byany object attached to the pipe and being drawn inwardly toward the areaof contact with the result that the pressurization of the cylinder 36will be transferred from the rod end to the base end with the resultthat the upper tire 26 is raised out of contact with the lower tire 26removing the danger of injury to the operator or damage to tools or theapparatus itself. atbsafi Because the upward force against the uppertire 26 tends to cause misalignment in the upper frame 32 with respectto the guide elements 34 a heavy cylindrical compression type spring 65is slidably mounted on each of the two guide elements 34 most remotefrom the tires 26 and is resiliently engaged between a portion of theframe 32 and an adjustable collar 66 rigidly releasably engaged witheach guide element 34 upon which a spring 65 is mounted. The effect ofthe springs 65 is to balance the upward force applied to the upper tire26 by an equal upward force applied bf the springs 65 to portions of theupper frame 32 remote from the tire 26 to give an approximate balancingof the forces applied to the frame 312 so that action of the cylinder 36in adjusting the height of the frame 32 is smoothly effected.

For the above description it will be noted that I have provided a newand improved method for pulling an object which maintains a high pullingforce regardless of variations in the cross section of the object anddoes not distort the object during the pulling thereon. Such method isparticularily desired in the pulling of a newly formed plastic object asit emerges from a continuous forming apparatus.

What I claim is:

1. The method of pulling an elongated object comprising; rotativelydriving at least one wheel member of a pair of wheel members supportedfor rotation about substantially parallel axes with each of said wheelmembers having radially deformable outer circumferential surfaces andwith at least one of said wheel members being bodily moveablesimultaneously with the rotation thereof towards and away from the otherof said wheel members with said axes being substantially parallel in allrelative positions of said wheel members; continuously applying duringsaid driving a force urging at least said one of said wheel members,which is bodily moveable, towards the other of said wheel members;continuously pulling an elongated object between said wheel membersalong an axis extending substantially normal to the plane containingsaid axes while maintaining adjacent portions of each of saidcircumferential surfaces in a deformed condition by engagement with theobject throughout the pulling thereof to provide a large area ofengagement with the object; and automatically releasing said forceduring such pulling and upon the pulling inwardly toward the area ofcontact between said circumferential surfaces of an undesired objectwhereby said one of said wheel members, which is bodily moveable, movesbodily away from the other of said wheel members.

2. The method as set forth in claim 1 in which only one of said wheelmembers is bodily moveable.

3. The method as set forth in claim 1 in which said driving is of atleast one of a pair of wheel members each of which has an encompassingpneumatic tire inflated to a pressure such that the outercircumferential surface thereof is readily deformable.

4. The method as set forth in claim 3 in which only one of said wheelmembers is bodily moveable.

5. The method as set forth in claim 1 in which the speed at which saiddriving occurs is variable.

6. The method as set forth in claim 1 and additionally counterbalancingthe force exerted by the object upon frame means supporting said one ofsaid wheel members which is bodily moveable.

References Cited by the Examiner UNITED STATES PATENTS 2,326,671 8/ 1943Patterson 226 2,525,590 10/1950 Collins 226186 X 2,670,926 3/ 1954Sewell et a1 226186 2,699,195 1/ 1955 Weller.

2,924,328 2/ 1960 Lidderdale 226176 3,132,787 5/1964 Rayfield 226176 M.HENSON WOOD, JR., Primary Examiner.

J. N. ERLICH, Assistant Examiner.

1. THE METHOD OF PULLING AN ELONGATED OBJECT COMPRISING; ROTATIVELYDRIVING AT LEAST ONE WHEEL MEMBER OF A PAIR OF WHEEL MEMBERS SUPPORTEDFOR ROTATION ABOUT SUBSTANTIALLY PARALLEL AXES WITH EACH OF SAID WHEELMEMBERS HAVING RADIALLY DEFORMABLE OUTER CIRCUMFERENTIAL SURFACES ANDWITH AT LEAST ONE OF SAID WHEEL MEMBERS BEING BODILY MOVEABLESIMULTANEOUSLY WITH THE ROTATION THEREOF TOWARDS AND AWAY FROM THE OTHEROF SAID WHEEL MEMBERS WITH SAID AXES BEING SUBSTANTIALLY PARALLEL IN ALLRELATIVE POSITIONS OF SAID WHEEL MEMBERS; CONTINUOUSLY APPLYING DURINGSAID DRIVING A FORCE URGING AT LEAST SAID ONE OF SAID WHEEL MEMBERS,WHICH IS BODILY MOVEABLE, TOWARDS THE OTHER OF SAID WHEEL MEMBERS;CONTINUOUSLY PULLING AN ELONGATED OBJECT BETWEEN SAID WHEEL MEMBERSALONG AN AXIS EXTENDING SUBSTANTIALLY NORMAL TO THE PLANE CONTAININGSAID AXES WHILE MAINTAINING ADJACENT PORTIONS OF EACH OF SAIDCIRCUMFERENTIAL SURFACES IN A DEFORMED CONDITION BY ENGAGEMENT WITH THEOBJECT THROUGHOUT THE PULLING THEREOF TO PROVIDE A LARGE AREA OFENGAGEMENT WITH THE OBJECT; AND AUTOMATICALLY RELEASING SAID FORCEDURING SUCH PULLING AND UPON THE PULLING INWARDLY TOWARD THE AREA OFCONTACT BETWEEN SAID CIRCUMFERENTIAL SURFACES OF AN UNDESIRED OBJECTWHEREBY SAID ONE OF SAID WHEEL MEMBERS, WHICH IS BODILY MOVEABLE, MOVESBODILY AWAY FROM THE OTHER OF SAID WHEEL MEMBERS.